1. Technical Field of the Invention
This invention relates to technology for processing vehicle information relating to a vehicle. More particularly, the invention relates to technology which uses a plurality of vehicle information obtaining means for obtaining vehicle information and transmitting that obtained vehicle information and an ID unique to each vehicle information obtaining means at regular intervals.
2. Description of Related Art
Japanese Patent Application Publication No. JP-A-2003-276410, for example, proposes a wireless wheel state monitoring apparatus for monitoring the state of a wheel provided on a vehicle. The wireless wheel state monitoring apparatus includes a plurality of transmitters, each of which is mounted on a wheel of a wheel/tire assembly, and a receiver provided on a body of the vehicle. Each transmitter measures the air pressure and the like of the tire of the corresponding wheel and transmits the obtained wheel information to the vehicle body-side receiver. The receiver then processes the wheel information received from the transmitter in a predetermined manner. In this case, unique identification data (ID) is assigned to each transmitter, and each transmitter transmits a signal containing both the wheel information and its own unique ID. Meanwhile, the IDs of all of the transmitters for the vehicle provided with that receiver are registered in advance with the receiver. When an ID contained in a received signal matches one of the registered IDs, the receiver processes the received signal.
When registering the ID of each transmitter with the receiver in this wheel state monitoring apparatus, a commander that is connected to the receiver by a cable is first brought close to the intended transmitter. Next, an operation switch of the commander is pushed such that a command signal (i.e., a trigger signal) is sent from the commander to the transmitter. A signal indicating that the operation switch is on is also sent to the receiver via the cable. The transmitter then transmits a reply signal containing its ID to the receiver in response to the command signal from the commander. Upon receiving the reply signal from the transmitter while the operation switch is on, the receiver stores the ID contained in the received signal.
Another example of technology for registering the ID of each transmitter with a receiver in this kind of wheel state monitoring apparatus is disclosed in Japanese Patent Application Publication No. JP-A-2000-103209, for example, which describes a system that performs ID registration by forcibly changing the tire air pressure. When registering the IDs of the transmitters with the receiver in this system, the tire air pressure is changed by letting air out of the tire, which is done by pushing a shaft portion of a tire air valve after a registration switch of the receiver has been turned on. Through this operation, the transmitter mounted on the wheel detects the change in pressure in the tire, such that, at that point the transmitter immediately transmits data to the receiver as an abnormal transmission. When the receiver receives the signal from the transmitter, the received ID is written in EEPROM.
An example of technology for registering the ID of a transmitter in a keyless entry system for a vehicle is disclosed in Japanese Patent Application Publication No. JP-A-9-256703, for example, which describes a vehicular ID system that forcibly sets a vehicle body-side receiver in a registration mode for a predetermined period of time after power starts to be supplied from a power supply to the receiver. In this system, the receiver is structured such that it is made to enter the registration mode for a predetermined period of time after power starts to be supplied from the power supply. When a user operates the transmitter while the receiver is in the registration mode, the ID of that transmitter is registered with the receiver.
As described above, however, using the commander and successively changing the tire air pressure in each wheel when registering the IDs require special equipment and a lot of labor, which goes against the demand to reduce labor in the production and maintenance processes of a vehicle. Further, with an apparatus such as that described above which monitors the wheel state, the transmission state of the transmitters and the like must be verified. During this kind of verification as well, it is necessary to eliminate, to the greatest extent possible, the equipment and labor required for that verification.